Jiří Hájek (Czech pronunciation: [ˈjɪr̝iː ˈɦaːjɛk]; 6 June 1913, Krhanice near Benešov – 22 October 1993, Prague) was a Czech politician and diplomat. Together with Václav Havel, Zdeněk Mlynář, and Pavel Kohout, Hájek was one of the founding members and architects of Charter 77.
Hájek studied and worked as a lawyer. From a young age he was a member of the Czechoslovak Social Democratic Party. During World War II Hájek was imprisoned (1939–1945). After the war he became a member of parliament for the Czechoslovak Social Democratic Party (1945–1948) and probably also a secret member of the Communist Party (code name E-22). During 1948 – 1969 he was a member of the Central Committee of the Communist Party of Czechoslovakia, during 1950 – 1953 he was the rector of the University of Economics.
From 1955 Hájek worked in diplomacy: in 1955–1958 as an ambassador in Britain, in 1958–1962 as a deputy of the minister of foreign affairs, and in 1962–1965 he represented Czechoslovakia in United Nations. Between 1965 and 1968 he was the minister of education. From April to September 1968, he served as the minister of foreign affairs in Dubček's government. After the Soviet Union army took control over Czechoslovakia (21 August 1968) he protested against this in a speech at the United Nations (where he used the word occupation) – this caused his dismissal from high offices and even from the communist party (1970).
Until 1973 Hájek worked in the Historical Institute of Czechoslovak Academy of Sciences.